Retinoblastoma.

Retinoblastoma (RB) is the most common intraocular malignancy of childhood, occurring in approximately 1 in 20,000 live births. It arises from pluripotential retinal progenitor cells. Mutations of the RB1 gene interfere with regulation of the cell cycle. Patients who harbor a germinal mutation of the RB1 gene are at risk for the development of second, non-ocular tumors.